多孔尖晶石型锰钴氧化物的制备和催化性能

Synthesis and Catalytic Properties of the Porous Spinel Cobalt-manganese Oxide

为获得高效催化还原对硝基苯酚的锰钴氧化物催化剂,以聚甲基丙烯酸甲酯为模板,采用硬模板法制备了具有三维有序大孔结构的尖晶石型锰钴氧化物(MnCo_(2)O_(4))。运用X射线粉末衍射仪、全自动物理吸附仪、扫描电子显微镜及紫外-可见分光光度计等对催化剂的结构和形貌进行表征,并研究其对硼氢化钠还原对硝基苯酚反应的催化性能。结果表明,多孔MnCo_(2)O_(4)催化剂具有立方晶相结构,其三维有序大孔孔径均一,比表面积达到65.7 m^(2)/g;与体相MnCo_(2)O_(4)和其他贵金属催化剂相比,多孔MnCo_(2)O_(4)催化剂表现出更优异的催化活性,对硝基苯酚还原的反应速率常数可达6.59×10^(-2)s^(-1)。多孔MnCo_(2)O_(4)催化剂在5次重复利用后对硝基苯酚的转化率仍高达90%以上。

In order to obtain high efficient cobalt-manganese oxide catalysts for the reduction of p-nitrophenol,spinel-type cobalt-manganese oxide catalyst with the three-dimensional ordered macroporous structure was synthesized using the polymethyl methacrylate hard-templating method.By X-ray powderdiffraction(XRD),Brunner?Emmet?Tellermeasurements(BET),scanning electron microscopy(SEM),and ultraviolet visible spectrophotometer(UV-Vis),the structure and morphology of the catalysts were characterized,and the catalyticperformances of the samples were evaluated for the reduction of p-nitrophenol by sodium borohydride(NaBH4).The results showed that the porous MnCo_(2)O_(4) catalyst with the uniform macropore size and the surface area of 65.7 m^(2)·g^(-1) possessed the cubic phase structure and exhibited more excellent catalytic performance than the bulk-MnCo_(2)O_(4) and some noble metal catalysts for the reduction of p-nitrophenol with the reaction rate constant of 6.59×10^(-2) s^(-1).Moreover,the conversion rate of p-nitrophenol wasstill more than 90%after the porous MnCo_(2)O_(4) catalyst was reused five times.